Stupidity, especially that kind of stupidity which supported by masses.
Well, i suppose Dr. Seuss books in general. For everyone - young and elderly. They have some good lessons. As for more adult books. H. G. Wells wrote alot of good books which i enjoyed. It's hard to pick any of them in particular, but when it's a single book..hm. Time Machine. Also 2004 movie adaptation is awesome.
Planetside 2. Had to grind last 80 certs and buy T2 striker.